The present invention is related to a method for adjusting a transmission characteristic of an electronic circuit and is applicable, for example, for the adjusting of hearing aids.
In the case of electronic circuits for processing an input signal into an output signal, the transmission characteristic, for example, the amplification, may depend on parameters of the input signal. Input parameters of this kind, in the case of a modulated input signal, are the amplitude or frequency of the input signal. An exemplary application of circuits of this type lies in the field of hearing aids. A modern hearing aid can be adjusted depending on the individual's requirements corresponding to the individual hearing impairment, wherein the amplification is to be dependent, on the one hand, on the frequency of the input signal and, on the other hand, on the input sound level.
A method for the adaptation of the transmission characteristic of a hearing aid to the hearing impairment of its wearer is taught in the U.S. Pat. No. 5,835,611. In the case of this method, the adjustable hearing aid is connected to a computer (personal computer) having a monitor and mouse. On the monitor screen, a transmission characteristic of the hearing aid is represented as a curve in a curve in a two-dimensional diagram. The acoustic specialist selects a segment of the two-dimensional curve and modifies the transmission characteristic by means of mouse movements, as a result of which certain operating parameters defining the transmission characteristics are changed. In this manner, the acoustics specialist adapts the transmission characteristic to a desired response. When a sufficient adaptation has been achieved, the adapted operating parameters are transmitted to the hearing aid and stored in the hearing aid's memory.
For the representation of the transmission characteristic, depending on the manufacturer of the hearing aid, two different two-dimensional diagrams are common. These are explained on the basis of the FIGS. 1–3.
In the so-called gain-view diagram, the amplification g (FIG. 1), resp., the output sound level Lout (FIG. 2) are indicated in function of the frequency f. Because the amplification g, resp., the output sound level Lout additionally is dependent on the input sound level, in the same diagram frequently the curves for several selected input sound levels are indicated.
In the so-called dynamic-view diagram-view diagram (FIG. 3), the output sound level Lout is indicated in function of the input second level Lin. Because the output sound level Lout in addition is also dependent on the frequency, within the same diagram frequently the curves for several selected frequencies are indicated.
The separation between two methods of representation is founded on the way of thinking of users, i.e., of the acoustics specialists.
The method divulged in U.S. Pat. No. 5,835,611 has various disadvantages. First of all, either the frequency f or the sound level Lin is considered as the input signal. During the adjustment, frequency both parameters g, Lin simultaneously have to be taken into consideration, which is either not possible or else, if at all, by means of a switching back and forth between the two methods of representation. The logical relationship between the diagrams has to be made in the mind of the user, which calls for a great degree of imagination. It has to be assumed that this relationship is not evident to all users. In the second instance, both methods of representation are confusing. Because, as described above and illustrated in the FIGS. 1–3, within the same diagram several curves are indicated, which respectively differ by the value of a further parameter Lin, f (FIG. 4). In doing so, every parameter value is assigned a colour, in order to enable differentiation between the parameters. For the user, however, it is not easy to conceive which curve belongs to which parameter; the diagram appears complicated. The more irregular the adjustment of the hearing aid is, the more confusing this method of representation becomes. It is conceivable that adjustments of hearing aids of the future generations will not anymore be completely recorded and represented with the known diagrams.